Dynamically adjusting board stacking system

Abstract

A board stacking system for stacking board layers into a stack, and associated method are provided. The board stacking system includes a board stacking apparatus adapted to arrange board layers into the stack. The board stacking apparatus having a stack holder comprising an adjustable stacking area for supporting the stack, the stacking area having a length defined between a front edge and a back edge. The board stacking apparatus further having one or more stacking arms operable to receive board layers from a board dispensing mechanism and sequentially arrange the board layers onto the forming stack. The board stacking system further includes a scanner positioned and configured for measuring a width of the board layers and transfer the information to the stack holder to allow adjustment of the length of the stacking area to substantially correspond to the width of the previously measured board layer.

The invention claimed is: 
     
       1. A lumber stacking system for stacking a plurality of board layers into a stack, the lumber stacking system comprising:
 a lumber stacking apparatus adapted to form the stack, the lumber stacking apparatus comprising:
 a stack holder comprising an adjustable stacking area having a support surface configured for supporting the stack, the stacking area having a length defined between a front edge and a back edge of the stack holder; 
 one or more stacking arms operable to receive a board layer and subsequently arrange the board layer onto the forming stack; 
 
 a lumber dispensing mechanism adjacent the lumber stacking apparatus and comprising:
 a conveyor for carrying lumber along a flow path; and 
 a stop operable to engage the flow path and prevent forward movement of the lumber along the flow path, the stop being adapted to allow the lumber to gather side-by-side and in abutment with one another along the conveyor to form the board layers, the stop being further operable to disengage the flow path when the board layer is formed to enable transferring individual board layers from the conveyor onto the stacking arms; and 
 
 a scanner positioned to monitor a section of the conveyor proximate the stop and configured for measuring respective widths of individual board layers blocked by the stop prior to being transferred to the lumber stacking apparatus, 
 the scanner being operatively connected to the lumber stacking apparatus and configured to transmit the measured width of a most recently measured board layer to the stack holder, wherein prior to each individual board layer being transferred onto the stacking arms, the stack holder is operable to dynamically adjust the length of the stacking area to substantially correspond to the width of the most recently measured board layer measured width. 
 
     
     
       2. The stacking system according to  claim 1 , wherein the stack holder comprises one or more movable stoppers operatively mounted proximate the rear edge adapted to move towards and away from the front edge to adjust the length of the stacking area. 
     
     
       3. The stacking system according to  claim 2 , wherein the movable stoppers are adapted to retain the board layer within the stacking area upon retraction of the stacking arms. 
     
     
       4. The stacking according to  claim 2 , wherein the stacking arms are operable between a receiving position where the stacking arms extend above the stack and across the length of the stacking area for receiving and supporting a corresponding board layer, and a retracted position where the stacking arms slide rearwardly from under the supported board layer, thereby dropping the board layer onto the stack. 
     
     
       5. The stacking system according to  claim 4 , wherein the movable stoppers have contact sensors configured to detect contact with the movable stoppers, and wherein displacement of the stacking arms into the retracted position is initiated upon engagement of a first dispensed board with the movable stoppers. 
     
     
       6. The stacking system according to  claim 1 , wherein each board layer includes a predetermined number of boards. 
     
     
       7. The stacking system according to  claim 1 , wherein the stack holder is further adapted to adjust a depth of the stacking area so as to lower the stack subsequently to the dropping of each board layer thereon. 
     
     
       8. The stacking system according to  claim 2 , wherein the stack holder comprises a controller adapted to receive the width of the layer of boards previously measured by the scanner, and wherein the controller is configured to operate the movable stoppers to adjust the length of the stacking area. 
     
     
       9. A method of forming a stack of lumber in a stacking area of a stack holder using boards being carried along a flow path, the method comprising:
 in a layer-forming step, gathering a plurality of boards side-by-side and in abutment with one another along the flow path for forming a board layer; 
 in a measuring step, measuring a width of the board layer using a scanner positioned to monitor a section of the flow path where the plurality of boards are gathering to form the board layer; 
 in a transmission step, transmitting the width of the board layer to the stack holder; 
 in an adjustment step, dynamically operating the stack holder to adjusting a length of the stacking area to substantially correspond to the width of the board layer; 
 in a transfer step, transferring the corresponding board layer in the stacking area; and 
 cyclically repeating the layer-forming step, the measuring step, the transmission step, the adjustment step and the transfer step until the stack is complete.